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Blanket statements are almost always wrong! (There is another blanket statement!)

To say something like, "I just think the pm6 cant handle 2 batteries of different voltages, and other lights can... simple as that" is neither helpful nor scientific in any way!

There is NO inherent difference in the electrical characteristics of the PM6 from any other incandescent light. There MAY be some MECHANICAL issue that damages the cell and thus creates a situation where the cell(s) may vent catastrophically, but simply issuing the statement above makes no sense and helps no one.

If the issue is simply a difference in charge, as you imply by saying, "pm6 cant handle 2 batteries of different voltages, and other lights can" then two otherwise similar lights will have the same exact action occur.

EVERY other 2 cell incandescent light is essentially the same as the PM6 ELECTRICALLY, the electrical portion is a circuit with an on/off switch closing/opening the circuit between a positive and negative battery pole, with the resistance of a lamp filament in between creating light. If it is just the way the PM6 handles the unbalanced charge, then EVERY tailcap switch, 2 cell light, should do exactly the same, because they are identical electrically.

Now the PM6 MAY be different because it allows more compression of the battery can, which by nature are pretty tough, but which can be made to fail with the proper MECHNICAL damage. Mechanical damage could include crushing or crimping, or even extreme heat. Since this light was not hot to the touch prior to the sudden incident, and surely would have been if thermal damage started the problem, the evidence would lean towards some other mechanical damage to the cell, assuming some 3rd variant such as cell chemistry issues, was not present.

However, since we now have 3 issues with PM6's, it appears there is some issue with that light, and the question of damage due to compression from an overly strong spring or head compression is very intriguing as a possibility. That is not necessarily a condemnation of the light, just a question of, "is it possible that the spring and/or head compression might be a contributor or the cause of the action."

Time will tell, I am interested in what we will find when the light goes back to Pelican, and I think that one of the caveats should be that they share what they find, unlimited, and without editing.

Bill

Only a virtuous people are capable of freedom. As nations become more corrupt and vicious, they have more need of masters. Benjamin Franklin

From looking at the pictures, it appears that the lithium in one (or both) of the cells ignited. Usually this can only happen if a cell develops an internal short circuit and goes into thermal runaway. If a cell is shorted externally, the PTC will cut out before the cell overheats. Reverse charging can cause lithium cells to short out internally.

It is, however, curious that the PM6 appears to be more prone to cell shorts than any of the dozens of other multi 123A lights on the market. If it was just a matter of bad cells escaping QC, failure rates would be more evenly distributed among twp cell lights and much higher (i.e. greater than near zero) for 3+ cell lights. The fact that CPF hasn't had a single vent with flame incident involving a three to six cell light--even though the risk for mismatch is up to three times higher than in two cell lights--suggests that batteries aren't the main causal factor here.

Pelican should take a good look at their product to see just what's going on here. Similarly, battery producers should take a good look at the PM6 to see if it's putting more physical pressure on the cells than they can withstand.

When mismatched cells are used together, one of the cells gets hotter than the others. If the cell gets hot enough, pressure builds up and it vents. If the vented gas is combustible and there is an ignition source, we have the possibility of flame.

Flamable gas is the least of all concerns when a primary lithium cell is charged.

The danger from charging lithium primaries is the formation of conductive lithium dendrites between the electrodes. These will internally short the battery. Short circuit currents will generate enough heat to ignite the electrolyte.

There is NO EVIDENCE that ANYTHING could have prevented the venting and breakdown of these cells. At this point everything is conjecture, though we can be pretty sure that at least one of the cells went into thermal runaway, determining after the fact what happened will be tough, since we have no idea of the state of the cells prior to the incident. We have to try to recreate the situation that triggered it.

BUT...you use the best tool you have, and currently that is the ZTS, or prehaps the Ansmann tester, and try to determine to the best of your ability the POSSIBLE causes of the failure and then work from there.

The ZTS and the Ansmann are not perfect, as Tom repeatedly points out, but it would take someone who has a significantly higher threshold for folly than I do to put 2 cells with sigificantly different test results in the same light. The results might not be perfect, but they do give a general idea of the state of the cell. It might be VERY general, but that is better than nothing!!

I have used simple open circuit testing for the last two years, and never had a failure, but that is probably not a very good test.

The test algorithms the ZTS and Ansmann use are better, but still not perfect, and bad cells will still test good sometimes and good cells will sometimes test badly. Amazingly, I find humans are much the same!!

But given the choice of open circuit testing or using either one, I'll take the ZTS or Ansmann, because at least they tell me SOMETHING is different about this cell, even if it might not mean that it really does have less capacity or charge than the other cells. It is DIFFERENT, and that alone will push me to use it in a single cell light or not at all.

That's why I lean toward using them, because it is better than what we do now, maybe only 1/2%, or 1%, or maybe 10% or even maybe 50% better, but still better, regardless.

As far as that goes, what is your expertise in testing and evaluation? Can you bring something to the process which will be helpful, because I'm sure we would all appreciate it, these kind of catastrophic failures need all the analysis they can get!!

Bil

Last edited by bwaites; 06-08-2006 at 04:09 PM.

Only a virtuous people are capable of freedom. As nations become more corrupt and vicious, they have more need of masters. Benjamin Franklin

At the risk of interrupting the petty bickering, does anyone have a way to check on the well being of Steve?

His last post did not sound real positive as far as his health was concerned and he does not seem to be responding to PM's. Has anybody been in touch with him or have a way to reach him [like a phone]?

......I was actually doing it outside a body, to avoid the pressurization issues and forceful expelling of gas or damage to a light. I could not make it happen, the cell just died......

I wonder if having it outside a body may be why you couldn't recreate a failure. Any hydrogen gas that may be building up is disappating in the air. If you retry this again, you might try something like placing it inside a ziplock bag or other airtight container that would keep any hydrogen gas concentrated but not allow enough pressure to build up to be dangerous. If you squeezed as much air as possible out of the ziplock before you started, you might be able to detect it inflating with released hydrogen and get an idea if a lot is being generated even if it doesn't ignite.

Of course, if that happens, you might want to call the bomb disposal squad to open the ziplock bag for you.

I'm having some thoughts:
1. Some flashlights, like the PM6, may apply more pressure than neccessary to the cells (stiff spring contacts).
2. The cells may hold up under the pressure of the springs under normal circumstances.
3. In some cases, minor manufacturing defects in cell-uniformity could lead to minor crushing and an internal short when used in "stiff spung" flashlights.
4. in other instances, The heat from the lamp, combined with the heat generated by the cells, may be enough- during a long-run, to weaken the cell- at which point, the high spring pressure can then deform the cell, (long shot on that one, doubtfull, but i'm thinking)...
5. Minor cell imperfections, combined with the high spring tension- combined with a unpressurized flight and the rigors of the shipment proccess, combined with the heat build up of a long run, may have created a senario where an internal short could occur....

This isn't a list of facts- just a list of ideas to throw in the mix...

I've now heard of several folks attemping to create a volitile reaction from a lithium battery by charging it(no success).... While I'm sure it could be done- I think an internal short in a battery with lots of juice left in it, would be the more likally cause of a violent reaction.. and would coincide with the light operating at "normal" brightness right up to the moments before it started to "do stuff."

For the reasons other people have mentioned; it seems likely that these events have mechanical causes external to the battery. I would suggest not using any devices in which these events have been reported.

I wonder if an internal short can be caused by damage to the can, such as damage by a too stiff spring? Does anyone know?

Second, if so, is the risk worsened under running conditions? An internal short wouldn't require current to be flowing, since the short is inside the can, and since that is the case, would it be worse or better if current was being drawn from the cell?

I CAN create venting, (putting cells in a fire is one way, among others), I just haven't been able to do using anwhere close to normal circumstances.

There ARE A LOT of variables at play here.

Bill

Only a virtuous people are capable of freedom. As nations become more corrupt and vicious, they have more need of masters. Benjamin Franklin

Here's a quick photo I snapped of two BS 123 cells, one with normal bottom and the other with a crunched bottom. Note that the crunched cell did NOT come out of the PM6, but rather from a single cell twisty light that apparently was overtightened. The PM6 spring, if memory serves, would cause this much or more crushing.

The specific model PM6 I'm talking about as "stiff-springed" is the hard anodized LED version of this light. I'm not sure if every PM6 has that same spring or not.

At the risk of interrupting the petty bickering, does anyone have a way to check on the well being of Steve?

His last post did not sound real positive as far as his health was concerned and he does not seem to be responding to PM's. Has anybody been in touch with him or have a way to reach him [like a phone]?

I have his phone number, and just spent about 20 minutes on the phone with him.

As his earlier post says, he was feeling quite sick since the incident, with a lot of nausea and vomiting. He also still has the rash over most of his body. He said that just when the phone rang, he was starting to feel a bit better and more like himself.

He wanted me to thank everyone for all the well wishes, and positive thoughts. He was amazed by all of the energy, and was especially impressed by the reaction of Kevin at Battery Station. He mentioned several times that he really appreciates all the steps that he (and many other members) are taking to solve this problem, and prevent it from happening again.

He apologized that he hasn't had the energy to reply to the PM's. But I don't think he'll be able to keep himself away for long I believe he's on his way to relax at the beach for a bit...

So to your point of view, everyone should just stop using their PM6's?

I guess that works, but it doesn't get us closer to either a way to prevent the problem from happening, (because it is NOT unique to PM6's as has been pointed out multiple times), or to figuring out what actually happened, nor does it do anything to attempt to distinguish between cells and what their values are and even if that plays a role.

At this point we have NO idea what caused it. There is no empirical evidence that a cell imbalance caused it, that mechanical damage caused it, or that the PM6 is the culprit for some unexplained reason.

If testing a bunch of cells with the ZTS or Ansmann and then keeping track of whether it ever happens with "matched" cells allows some evidence, then I'm all for it. Until someone comes up with a better plan, that's the one I'll buy into.

BTW, SilverFox's occupation is a little unique, you should maybe ask what he does for a living. But quietly, in a PM so you don't embarrass yourself or him.

Bill

Only a virtuous people are capable of freedom. As nations become more corrupt and vicious, they have more need of masters. Benjamin Franklin

So to your point of view, everyone should just stop using their PM6's?

I did not say that. I said that anyone who is so worried about explosive venting events that they will employ magical talismans such as MBT testing would be much better served by not using the PM6.

I guess that works, but it doesn't get us closer to either a way to prevent the problem from (because it is NOT unique to PM6's as has been pointed out multiple times), or to figuring out what actually happened, nor does it do anything to attempt to distinguish between cells and what their values are and even if that plays a role.

Neither does employing the MBT as a magical talisman.

At this point we have NO idea what caused it. There is no empirical evidence that a cell imbalance caused it, that mechanical damage caused it, or that the PM6 is the culprit for some unexplained reason.

Agreed, all the more reason that MBT testing is a joke.

If testing a bunch of cells with the ZTS or Ansmann and then keeping track of whether it ever happens with "matched" cells allows some evidence, then I'm all for it. Until someone comes up with a better plan, that's the one I'll buy into.

Some controlled experiments could be useful. This event happens rarely enough though that anectdotal reports will be worthless for determining if MBT characterisation of cells is of any value.

BTW, SilverFox's occupation is a little unique, you should maybe ask what he does for a living. But quietly, in a PM so you don't embarrass yourself or him.

Some common safty features you see in other lights are:
1) Presence of a Hydrogen absorbing catalyst
2) Pressure relief vent.

Most mods and CPF small runs don't have either.

Questions:
-Would either of those help?
-Will the internal PTC of a CR123 even work if the pressure on the outside of the cell is really high from previous venting? (as it might be in a fully sealed light)
-When the PTC trips does it cut off current permantly or only release some gas until its equalized and then continue to work?

Ok, please pardon my ignorance with this question about the ZTS tester. Is this something that is a simple uncomplicated, affordable thing that us regular folk can buy and use or is a a big technical machine of some sort? Pictures of it?

**NEVERMIND** I see it on batterystations website....

More importantly, I really hope LM is going to be ok! And I'm really glad to see the cool heads between the parties that are involved. Nobody is talking about suing the other and what not, which is cool. I know that I'm not going to stop buying BatteryStation batteries. Even considering the occurances that we know of, its still and extremely rare event. Heck, what is it, less than one in a million? Three million? We should definetly look into this of course, but I don't think anybody should be scared to use these batteries or lights.

Sorry in the above I got the PTC (tempeture cutoff) confused with the pressure vent. I'm not sure but the pressure vent seems to be activated by a spike through the diaphram, which would be permanant once it happened, but I assume the battery would continut to opperate. The PTC seems to cutoff current and reset itself.

You may want to mention this to your physician, sounds like it could be important.

Please keep us posted.

I'll stress it again. Fluorine is tremendously reactive. Many things that you thought were non-flammable will burn spontaneously if exposed to a stream of fluorine gas. In the body it bonds ferociously with Calcium. The damage can progress over time and can be much worse below the surface than it initially appears. Calcium means bones, of course, but is also essential to nerves, and heart. There is at least one specific treatment (calcium gluconate), but it has to be administered early enough. It presents the Fluorine with readily available Calcium, to spare the body.

pm box is full, tried email. If anyone knows how to get a message to Lunarmodule, I think this is important, especially since he is feeling worse. The tissue turning BLACK is symptomatic of HF exposure.

Wow!

First off, let me say I hope there's no lasting injuries and I'm sure your foot will feel better when it quits hurting...

Secondly, I must say I am impressed that the BatteryStation people are standing firmly behind the batteries, offering to replace everything to make it right. This is very impressive, especially as we can't say with 100% certainty that they batteries were new / at fault. ('Probably' doesn't cut it with some vendors!)

I know I use Battery Station Lithium 123s with confidence, although I don't think I'll encourage any of my students to use incadescent lithium lights for long-term lighting!

Lunarmodules comment was worth its weight in GOLD, folks!

The main point I want to get out to anyone who reads this is to know the warning signs: very, very, very short notice. The pressure release was extremely sudden and violent. I did have ten seconds or so that I could have used to throw the light away, behind a piece of furniture or into a box to contain the damage / shield myself. What I can recommend is if anyone feels their light vibrate, smells a pungent chemical odor, and/or sees or hears a rushing sound of gas like steam from a tea kettle come from the light, THROW IT AWAY FROM YOU AND ANYONE ELSE NEARBY. Treat it exactly like a firework (like a big bottle rocket) with the wick lit. Dont try to switch it off, although it may help, it may not.